The long range goal of this lab is to understand the neurobehavioral processes during the developmental organization of attention and preparatory behavior in nonhandicapped and mentally retarded individuals. The brain event-related potential (ERP) provides electrophysiological measures of neural function related to information processing. In contrast to most behavioral measures which are discrete and delayed relative to the process being studied. ERPs provide an immediate and continuous record of brain activity. Our paradigm allows the concurrent study of cognitive- related late ERP components and behavioral measures of information processing in the infant It is necessary to determine the effects of some basic variables in order to understand the relationship of the late ERP to the infant's information processing. We will investigate three different components of the infant's ERP complex designated NSW, Pb, and Nc. They are presumed to be manifestations of the infant's attention, memory, and expectancy processes. We have adopted converging strategies to elucidate the functional significance of the three components. The first strategy will manipulate basic experiential variables of event familiarity, association, and discriminability that affect the infant's attention, formation of memory, and expectancy in order to determine their effects on the components. Second, Down syndrome (DS) infants will provide a contrast group with altered neural development for determining effects on specific aspects of attention, formation of memory, and expectancy. These studies will elucidate specific DS characteristics and their neuroelectric bases. The third strategy will explore techniques for the possible localization of regions within the brain generating the components. The studies will contribute to our understanding of the functional development of cortical systems involved in infant information processing, and specifically the neurobehavioral processes of Down syndrome infants.